Loom dobby mechanism



Dec. 10, 1929. w. M. WATTlE 1,739,194

LOOM DOBBY MECHANISM Filed July 10, 1928 3 Sheets-Sheet 2 f/n e/rfar Wm 11 Mm Dec. 10, 1929. w, wATTlE 1,739,194

LOQM DOBBY MECHANISM Filed JulylO, 1928 I Sheets-Sheet 3 HIM/fem M Mil /c f dfif Patented Dec. 1( 1929 UNITED STAT B PATENT OFFICE WILLIAM M. WATTI 0 WORCESTER, MASSACHUSETTS, ASSIGNOR To CROMPTON & KNOWLES LOOM WORKS, 0F WORCESTER, MASSACHUSETTS A CORPORATION OF,

MASSACHUSETTS Application filed July 10,

This invention relates to dobby mechanism for raising and lowering the warp harnesses in aloom. The invention relates more particularly to looms for weaving silk or other fine fabrics, in which a considerable number warp threads are drawn through each reed space. In such looms it is sometimes necessary to shift all or nearly all of the warp threads 'in a particular reed space at the same time, thus crowding the reed at the point where the warps pass each other to such'an extent that considerable warp breakage frequently occurs.

It is the object of my invention to provide mechanism for varying the relative movements of different Warp threads, splitting the Shed so that the warp threads will pass each other successively rather than simultafioiislyJ i i Y Inthe' preferred form, my invention consistsfin'th'e provision of improved actuating mechanism for the "dobby knives, by which the relative movements of the knives areaccelerated or retarded'to throw the associated harnesses out of step with each other,

fMy invention further relates to arrange: merits and combinations oflp'art's which will be hereinafter described and more pa'rticu larly pointed out in the appened'claim's'.

preferred form of the invention is shown in the drawings in which Fig. 1 is a front view of a dobby'mechanism embodying improvements;

Figs. 2 and 8 are deta1l plan v ews of certai'n"parts, lookingin thedirections of the proverdobby mechanism,andlooking the direction ofthe arrows 7 and 8 in'Fig. 2; and

i Fig. 9 is a diagrammaticplan view, illustrating the relative movements of the dobby knives. I Y

' Referring to the drawings, I have shown LOOM DOBBY MECHANISM 1928. Serial No. 291,653.

a portion of a loom frame 10 in which a number of harness jacks 11 are pivoted to swing about a shaft or stud 12, each jack being connected to a lever 13 having upper and lower dobby hooks 14 and 15.

Knife bars 16 and 17 (Figs. 2 and are slidable in upper and lowerjslots 18 and'19 (Fig. 1) and the dobby hooks are selectively engaged therewith by mechanism controlled from a pattern chain 20. The parts thus far described are of the usual construction and in themselves form no part of my present invention.

Actuating levers 22 and 2 3 are mounted on a cross shaft 24 and the lever 22 is provided withan arm 25 connected by a link, 26 and rod 27 to anyusual actuating mecha nism, not shown. The levers 22 and 23 are thus rocked alternately'i'n' opposite direc tions, being moved in one direction or the other at each pick of the loom. It is customary to make the rear rocking lever 23 longer than the front rocking lever 22, so as to give an increased lift'to the rearward harnesses'and this construction I have retained inmy' improved (lobby mechanism. This'causes the rear ends of the knifebar s to travel somewhat further than the forward ends "thereof.

I havealso provided special connections between the rocking levers 122' and 23 "and the knife bars'16 and 17 which their relative'movements are'still further varied.

Referring to Figs. 1 and'3', I have shown the upper 'end of'the front rocking lever 22 as pivotally' connected at 30 to a' short link 31,"which in turn is pivoted on astud 32 mounted in a link 33, turning about a" pivot 34 fixed in the loom frame 10.

A link block 36 is also pivoted on the stud 32 and is connected by a threaded rod 37 and head 38to a stud or gudgeon 39 in the end of the upper knife bar 16.

In the upper part of Fig. 7, I have indicated the end and mid-positionsof the lever 22, together withthe corresponding positions of the front end of the upper knife bar 16. From this diagram it will appear that the stud 32 is constrained to move in an are independently of the arc of movement of the stud 30 and that the relative movement of the stud 39 is thus modified, so that the movement is relatively greater during the first half of the movement of the lever 22 and relatively less during the last half of such movement-.

Referring again to Figs. land 2, the lower end of the lever 22 is connected by a link 40 to a stud 41, which in turn is supported in a short link 42 pivoted to the frame 10 at 43.

A link block 44 is also pivoted on the stud 41 and is connected by a rod 45 and rod head 46 to a stud or gudgeon 47 on the front end of the lower knife 17.

Reference to Fig. 7 indicates that the pivot 41 is constrained to move in a short arc independent of the motion of the link 40 and that the travel of the stud 47is varied, so that the first part is relatively greater and the last part relatively less than the corresponding movements of the actuator lever 22.

At the upper end of the rear lever 23 (Fig. 4) I have provided connections similar to those at the lower end of the front lever 22, such connections comprising a link 50 pivoted at 51 to a link 52, which in turn is pivoted at 53 to the frame 10. The stud 51 is mounted in avbearing in the end of a lever 54, pivoted on a stud or gudgeon 55 in the front end of the upper knife 16.

The operation of these connections is similar to those previously described and is illustrated in the upper part of diagram Fig. 8. a

The lower end of the rear lever 23 is connected by a stud and link 61 to a stud 62 pivoted in the end of a link 63, which in turn is mounted on a fixed pivot 64. A second link 65 connectsflthe stud 62 to a stud or gudgeon 66 in the rear end of the lower knife bar17.

The relative movement of the stud or gudgeon 66 during the rocking of the lever 22 is clearly indicated in Fig. 8. When the levers 22 and 23 are moved together in the direction of the arrowsa in Figs. 7 and 8, the front end of the upper knife bar will move more rapidly at first and more slowly toward the end of the stroke, while the rear end of said knife bar will move more slowly at first and more rapidly towards the end. Similarly, the front end of the lower knife bar 17 will move more slowly at first and more. rapidly later, while the rear end of the lower knife bar will move more rapidly at first and more slowly later.

'The relative movements of different parts of the two knife bars are thus thrown out of harmony, These relative positions of the upper and lower knife bars during different' portions of the travel thereof are substantially as shown in Fig. 9, in which the full linesrepresent successive positions of the upper knife bar 16 and the broken lines indicate corresponding positions of the lower knife bar 17.

At the extreme or normal positions the knife bars are indicated as closely adjacent and side by side, such indication being adopted for the sake of clearness in the diagram.

It will thus appear that the initial and final positions of the knife bars are substan tially unchanged from ordinary commercial practice, but that the intermediate positions are assumed in an entirely different time ratio.

The raising and lowering of the harnesses is thus accomplished at different speeds, according as they are controlled by the upper or lower knife'bar, and the warp threads reach the center point successively rather than simultaneously. The shed is thus split effectively and the breakage of warp thread by crowding in the reed is substantially eliminated.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is 1. In a loom dobby, a knife bar, an actuating lever for each end thereof, means to rock said levers, and connections from each actuating lever to one end of said knife bar,

said connections being effective to acceleratethe movement of one end of said knife bar and to simultaneously retard the movement of the other end of said knife bar relative to the movement of the points of connection of said actuating levers.

2. In a loom dobby, aknife bar, an actuating lever for each end thereof, means to rock said levers, and connections for each actuating lever to one end of said knife bar, said connections being effective to accelerate the movement of one end of said knife bar and to retard the movement of the other end of said knife bar relative to the movement of the points of connection to said actuating levers during the first part of a stroke thereof and to reverse said acceleration and retardation toward the latter part of the same stroke.

3. In a loom dobby, a knife bar, an actuating lever, a connection between said lever and one end of said knife bar, and means to rock saidlever, said connection being effective to cause the end of said knife bar to move at a speed differing relatively from that of the point of connection to said actuating lever.

4. In a loom dobby, a knife bar, an actuating lever, a connection between one end of said lever and one end of said knife bar, and

means to rock said lever, said connection being effective to cause the end of said knife bar to be moved relatively toward the end of saidlever and away from the end of said lever i113 different parts of the movement of said ever.

5. In a loom dobby, a knife bar, an actuating lever, a connection between one end of said leverand one end of said knife bar, and means to rock said lever, said connection being effective to cause the end of said lever to move at greater and less speeds than said end of said actuating leverduring a single continued movement of said lever.

6. In a loom dobby, a knife bar, an actuating lever for each end thereof, means to rock said levers, and connections from each actuating lever to one end of said knife bar, said connections each including a link pivoted to an end of one of said levers, a second link connecting said first link to an end of one of said knife bars, and a third link connecting the joined ends of said first and second links to a pivot fixed on the dobby frame.

In testimony whereof I have hereunto affixed my signature.

WILLIAM M. WATTIE. 

